Emergency medicine, as it is practiced today, can take place in a diverse variety of locations. These include, but are in no way limited to hospital emergency rooms, military field hospitals, in ambulances and medical aircraft, and at the scene of injury or other trauma. For obvious reasons, the amount and type of equipment that is available to the emergency personnel at such locations also varies considerably. However, with the advent of the Internet and availability of networks and wireless communication systems, it is now possible for the emergency personnel to have relatively real time access to many sources of information to assist them in performing their tasks.
A central fact that exists in emergency medicine is that a high percentage of the critically ill patients that arrive at an emergency care facility, such as a hospital's emergency room, are unconscious, confused, demented or otherwise unable to assist the emergency physician in any way. This occurs regardless of whether the patient is the victim of a naturally occurring event such a heart attack or a stroke, trauma, such as a wartime injury, an automobile accident, a sports related injury, or another event, such as a drowning. Also, it is frequently the case that no one else, whether friend or relative, is available to assist the physician by providing meaningful information about the patient, including medical history, currently taken medications, allergies, and the patient's weight. The emergency personnel are, therefore, today required to use primarily only their powers of observation to make determinations, such as the weight of the patient, before setting out to administer life-saving treatments to the patient.
Moreover, due to the critical nature of emergency medicine, the physicians and other personnel are often required to make decisions as to the care to be provided to a patient very quickly and without the ability to consult with others more specialized in treating specific conditions or to consider carefully the potential ramifications of the variety of possible treatments available. Without question, this need to act promptly can cause selections of treatment options to be made that may not always be optimal or even considered.
One of the most powerful weapons that the emergency medical practitioner has today in treating the patients that arrive for care in an emergency department is the scope of medications available that can provide an immediate benefit to the patient. The benefit is that of assisting the practitioner in stabilizing the patient until further diagnosis of the patient's condition can be made and more specific treatment protocols established. These medications range from drugs, such as epinephrine, that stimulate the sympathetic nervous system in cardiac patients to morphine and fluids for burn victims. The failure to administer the proper dosages of such medications to the patient can itself cause problems for the patient. For example, with epinephrine, an inadequate dosage may, in the worst case, cause a failed resuscitation resulting in death. Even when the patient survives, an underdosage may well result in anoxic injury, i.e., injury to the brain and other vital organs due to oxygen deprivation during a cardiac arrest. An overdose of epinephrine, on the other hand, can cause hypertension, tachycardia, cardiac dysrhythmia, cardiac injury and death. See, e.g., Campbell, Cardiovascular Effects of Epinephrine Overdose: Case Report, Anesthesia Progress, November-December 1977, at 190-194. Similarly, with the use of morphine to control pain in burn victims, an inadequate dosage may cause unnecessary pain and suffering for the patient. In turn, this can result in abnormal vital signs as the pain can trigger a stress response which could confuse the emergency personnel into thinking that an elevated heart rate is the result of improper fluid resuscitation when, in fact, it is cause by the patient's pain. An overdose of morphine will cause a decrease in blood pressure, respiratory depression or arrest requiring airway management and possibly even death, particularly where the emergency occurs in the field away from modern hospital conditions.
Also, in many emergency situations, there is an immediate need to establish a viable airway to enable the patient to breathe or assist with ventilation while other treatment is being accomplished. For example, with many burn victims, the inhalation of either or both of hot gases and smoke can result in swelling of the patient's airway, either immediately due to injured tissue or later as edema occurs. To accomplish this, the emergency physician uses medications, such as Etomidate and Succinylcholine, to paralyze the patient's airway so that optimal conditions exist for an advanced airway to be inserted between the vocal cords. The amount of Etomidate and/or Succinylcholine that must be administered in order to accomplish this paralysis is closely defined by the weight of the patient. If the dosage applied to the patient is too great, the necessary paralysis is accomplished, but there is a danger that other vital functions of the patient may be affected deleteriously thereby creating a greater risk of the patient not surviving. Conversely, if the dosage is too small, the needed paralysis is not achieved and the patient will fight the insertion of the advanced airway, often resulting in missed or unobtainable airways. Inasmuch as, when accurate patient weights are not known, those weights today are generally nothing more than the best estimates made by the emergency personnel present and are often done under considerable time pressure. Thus, these estimations can be quite inaccurate, particularly in cases where the patient is morbidly obese, an event that is not at all uncommon today, particularly in the United States. While this condition is more frequently seen in urban environments, it is now a fact of life nearly everywhere in this country. Morbidity in the United States continues to increase in prevalence. Predictions in the literature reflect an increase of obesity over the next several decades. See, e.g., Wang et al., The Obesity Epidemic in the United States—Gender, Age, Socioeconomic, Racial/Ethnic, and Geographic Characteristics: A Systematic Review and Meta-Regression Analysis, Epidemiologic Reviews, Vol. 29, 6-28 (2007). When this unknown weight estimation is compounded with the often anatomically difficult airway, the likelihood for a failed advanced airway increases significantly. The failure of insertion of an advanced airway, besides resulting in the loss of the time needed to address the underlying life threatening problems, results all too frequently in an adverse event, either a disfiguring and technically difficult surgical airway or, on occasion, death.
In the pediatric setting, the issue is even more critical. Errors of only a few pounds, or in the case of newborns, even just a few ounces, can cause patient weight errors that are many percentage points away from the patient's actual weight. Because mathematical errors in working with young patients can and do occur, which errors can be fatal, see, e.g., Kaushal, et al., Pediatric Medication Errors: What do we Know? What Gaps Remain? Ambulatory Pediatrics, Vol. 4, No. 1, 73-81 (January-February 2004), a need for accurately defining the weight of such patients clearly exists. The dangers of the incorrect delivery of medications to young children stem from many sources, including the need to dilute medications standardly prescribed for adults in an undiluted condition and the inappropriate labeling of differing concentrations of medications. Campbell, Cardiovascular Effects of Epinephrine Overdose: Case Report, supra. See also, Ornstein et al., Possible medical mix-up for twins: State is investigating an incident involving actor Dennis Quaid's infants at Cedars-Sinai. Medical overdose is suspected. Los Angeles Times, Nov. 21, 2007, at B1, where three infants were administered heparin at a dosage 1000 times greater than prescribed for the infants' weights.
Another situation that occurs frequently in emergency departments is what is known as procedural sedation. In this case, a fast-acting and short-lived sedative medication, such as propofol, is given to the patient to sedate the patient only long enough to perform some needed, but painful procedure, such as the reduction of a fracture or the suturing of a wound. Propofol is a weight (and age) dependent medication, the administration of which needs to be carefully calculated and monitored. See, e.g., Milner et al., Clinical Practice Advisory: Emergency Department Procedural Sedation with Propofol, Annals of Emergency Medicine, Vol 50, No. 2, August 2007.
However, one of the most perplexing problems that face the emergency personnel in addressing such treatment protocols properly is determining as accurately and quickly as possible, the weight of a patient, particularly when the patient cannot assist in that determination, such as by standing on a scale, because of his or her physical condition. The weight of a patient is important in that many of the medications that ought to be administered to such patients in order to stabilize their condition and keep them alive until further treatment can be administered, are ones where the dosage to be administered is closely dependent upon the weight of the patient. Similarly, particularly in the case of small children, the size of an uncuffed endotracheal tube that may be used on the child and the endotracheal tube per se are, under some formulae, weight dependent, although some formulae use the patient's age for selecting the tube size.
The problem of a patient weight determination when actually weighing the patient is not feasible has several facets, three of which must be addressed always to attain a relatively accurate weight. The first such facet is the general size of the patient. Is the patient a baby, a small child, a teenager or an adult; is the patient slender or obese; and is the patient in possession of all of his or limbs. Secondly, how is the patient clothed. Third, what life support equipment is now associated with the patient. Many other factors may also present themselves in specific situations as well. Presently, the attendant emergency medical personnel must deal with these factors primarily through rapid and subjective evaluations and estimations.
Turning to the first of these factors, this one is of particular importance in the two extremes, young children, particularly babies, and grossly overweight adults. Going initially to the situation with young children, for many years, it has been the standard procedure to use the so-called Broselow color-coded tape system to estimate the weight of a child. This device divides children into several weight categories based solely upon their length and a different color is assigned to each weight category. Then, the Broselow system allows the physician to utilize equipment and to prescribe drug dosages for a child, which drugs and equipment are stored and correlated according to the color on the tape that is associated with the length that the child measures. This tape system assumes necessarily a standardized weight for a child of a specific length. However, in recent times, particularly in urban environments in the United States, it has become known that many children of a given length do not have a weight that corresponds at all accurately to the innate assumptions of the color-coded system on the Broselow tape. Most frequently, such children are from mildly to highly obese for their length, although, in the case of malnourished or otherwise extremely slender children, an over-estimation of their weight may also occur. Hence, the color-coded Broselow system fails frequently to provide accurate estimates as to the medicinal dosages and equipment that are appropriate for the child, usually, because of the underestimation of the child's weight by the Broselow color-coded system. The dosages thus suggested by the Broselow system, therefore, are too low thereby endangering the child at a critical time. Since these determinations are being made when the child is either badly injured or critically ill, an improper application of the drugs or equipment to the child serves to further endanger the child's life. This problem has been discussed at considerable length in Nieman et al., Use of the Broselow Tape May Result in the Underresuscitation of Children, 1011-1019 Journal of the Society for Academic Emergency Medicine, 2006. Additionally, the Broselow color coded tape system ends at a standardized weight of 36 kg. Thus, children of a weight greater than this, based upon their assumed weight from their length, are simply left out and are subject solely to a weight evaluation by the attendant personnel. Hence, a need has been demonstrated for a better and more inclusive system for weight determination in young children. The need for an accurate weight determination rather than a subjective estimation is critical during the resuscitation process as well as during the initial care of the critically ill.
Similarly, while many emergency medical personnel are probably quite adept at estimating the weight of those adults who are of relatively normal physical builds, it is very different when the patient is obese. In most emergency departments today, it is not uncommon to encounter patients who weigh upwards of 400 pounds and often much more. In fact, the problem is so great that most hospitals today are forced to have equipment, such as wheelchairs, stretchers or gurneys, and beds, that are designed and built expressly to support such morbidly obese patients. Such individuals' weights are difficult for emergency personnel to estimate accurately and no system for overcoming this critical problem is known to date to exist to assist with these individuals' resuscitations.
A similar situation occurs when the patient is missing one or more limbs, whether by injury or congenitally. This occurs not only in hospital emergency departments, but more frequently in military hospital settings. Such individuals' weights are necessarily less than the comparable weight for an otherwise identical person with all of their limbs and the appropriate dosages of medications for such individuals must correspond to their present weight, which would be less than that which would be prescribed for a like individual with all of his or her limbs. Hence, proper allowances need to be made for such situations.
Patients arriving in the emergency departments come dressed in as many different ways as can be imagined; however, few are completely unclothed. Frequently, because of the nature of the injuries or other condition of the patient, it is either impossible or impractical to remove the clothing before initiating treatment. Most are dressed normally for the ambient conditions. But, even so, how they are dressed can vary very widely. For example, during summer months, one is likely to have patients dressed casually in light clothing weighing only a pound or two, whereas during the winter, particularly in more northerly and southerly regions of the world, people may well be dressed in very heavy clothing weighing many pounds. For obvious reasons, the more voluminous and heavy the clothing worn by a patient, the more difficult it is for the attending personnel to make accurate estimates of the person's actual weight. Also, the patient's occupation may effect the weight of his or her clothing; construction workers typically wear heavy, steel toe reenforced shoes or boots, police officers may have their weapons belts strapped to them and be wearing body armor. Soldiers in combat often have as much as fifty to sixty pounds of equipment on them. Included in this equipment can be a complex system of body armor and ballistic plates that are difficult to remove quickly, particularly in the event of a life threatening injury. Yet, an accurate estimation of the patient's weight may be a critical factor in providing the necessary medical care.
Moreover, the condition of the clothing on the patient can greatly affect their weight upon arrival in the emergency theater. Wet clothing weighs a considerable amount more than does dry clothing. For example, a Minnesota ice fisherman who has fallen through the ice before being rescued is likely to have twenty or more pounds of wet clothing when arriving for emergency treatment.
Finally, there is the question of the weight of equipment that a patient has with him or her upon arrival for emergency care. Very frequently, the patient will be strapped to a back board to prevent him or her from inadvertently moving and causing additional injury. Also, in order to assist the patient in breathing, oxygen may be in use so that the weight of the oxygen bottle and breathing apparatus is present. If bones have been broken or dislocations have occurred, splints or other apparatus to prevent movement of the limb may be in use. The weight of all such equipment must be taken into account when determining the actual weight of the patient.
The need for determining periodically the weight of an individual confined to a hospital bed as a part of an overall treatment protocol has been recognized for some time and a number of devices to accomplish this determination have been suggested. Three such systems are shown in Hasty et al., U.S. Pat. No. 5,393,935, Foster et al., U.S. Pat. No. 5,672,849, and Wilkerson et al., U.S. Pat. No. 7,381,910. Each of the previously disclosed systems has, however, addressed only the situation where the patient is bedridden and the important information is simply whether the patient's weight has changed materially over time. None has addressed the need for weight determinations under emergency conditions when the patient's life is in jeopardy, the patient is not completely undressed, and likely has some life support equipment on or very nearby. Nor has any allowed for a correction of the measured weight of a patient based upon a predetermined and known weight for various items of clothing and or equipment then associated with the patient. Additionally, while the weight of the patient can be determined while the patient is in bed, these systems do not interface with a real time computer system with a data base that can immediately assist the emergency care physician with the care and resuscitation when critically ill nor provide treatment algorithms for suggesting alternative modes of treatment or the potential of dangerous interactions between medications.
Also, it has been recognized that computer systems, networks and the Internet can be utilized effectively in monitoring patients' conditions and directing appropriate care to the patients, including the application of medications. See, e.g., Fu et al., U.S. Pat. No. 4,803,625. However, to the applicant's knowledge, no such computer system has been devised for accurately estimating the weight of an emergency patient and then utilizing that weight to suggest appropriate treatment, as well as the appropriate dosages of drugs and other medications for life saving treatment of emergency patients.
Adverse drug events caused by medication errors represent a common cause of patient injury in the practice of medicine. Many medication errors are preventable and, hence, particularly tragic when they occur, often with serious consequences. The enormous increase in the number of available drugs on the market makes it all but impossible for physicians, nurses, and pharmacists to possess the knowledge base necessary for fail-safe medication practice. Indeed, the greatest single systemic factor associated with medication errors is a deficiency in the knowledge requisite to the safe use of drugs. It is vital that physicians, nurses, and pharmacists have at their immediate disposal up-to-date drug references. Patients who are presented for care in emergency departments are usually unfamiliar to their emergency physicians and nurses, and the unique patient factors affecting medication response and toxicity are obscured. An appropriate history, physical examination, and diagnostic workup will assist emergency physicians, nurses, and pharmacists in selecting the safest and most optimum therapeutic regimen for each patient. Emergency departments deliver care “24/7” and are open when valuable information resources, such as hospital pharmacists and previously treating physicians, may not be available for consultation. A systematic approach to the complex problem of medication errors is needed to help emergency clinicians eliminate preventable adverse drug events and achieve the goal of a zero-defects system, in which medication errors are a thing of the past. New developments in information technology and the advent of electronic medical records with computerized physician order entry, ward-based clinical pharmacists, and standardized barcodes promise substantial reductions in the incidence of medication errors and adverse drug events. Emergency department patients expect and deserve nothing less than the safest possible emergency medicine service. See, e.g., Peth, Medication errors in the emergency department: a systems approach to minimizing risk. Emergency Medical Clinics of North America, Vol. 21, No. 1, 141-58, February 2003.
It has been suggested that modern information technology may be a means for resolving many of these errors; however, to date no such systems are available commercially. See, Barker et al., How can information technology improve patient safety and reduce medication errors in children's health care?, Archives of Pediatric and Adolescent Medicine, Vol. 155, No. 9, 1002-7, September 2001.
Finally, no known system provides the ability, when used in a hospital environment of creating a real time record of emergency treatment, including all of the medication delivered to the patient which can then be accessible at any time during the patient's continued stay in the hospital, whether within the emergency department or elsewhere.